From 1982 to 1989, the cyclophosphamide/doxorubicin/vincristine/etoposide combination was the standard treatment for small cell lung cancer in our center. Radiotherapy was started after three cycles, since little further response to chemotherapy could be expected. In 1989, ifosfamide replaced cyclophosphamide, and preliminary results from a pilot study showed impressive early responses. By December 1993, 36 patients had been evaluated, 20 of whom had limited disease and 16 of whom had extensive disease. The response rate was 81% after one cycle and 86% after the second cycle. Median survival time in patients with limited disease was 12 months; in those with extensive disease, it was 7.5 months. Five patients with limited disease are alive and fully active, with an observation time ranging from 29 to 58 months. Based on these findings, our standard treatment protocol has been revised to institute radiotherapy after two cycles of chemotherapy.